/*
 * Copyright 2011 The IEC61850bean Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package com.beanit.jositransport;

import javax.net.SocketFactory;
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;

/**
 * This class implements a client Transport Service Access Point (TSAP) over TCP/IP as defined in
 * RFC 1006, ISO 8072, and ISO 8073. It can be used to create TConnections that connect to remote
 * ServerTSAPs.
 */
public final class ClientTSap {
    public byte[] tSelRemote = null;
    public byte[] tSelLocal = null;
    private int maxTPDUSizeParam = 16;
    private SocketFactory socketFactory = null;
    private int messageTimeout = 0;
    private int messageFragmentTimeout = 60000;

    /**
     * Use this constructor to create a client TSAP that will start connections to remote TSAPs.
     */
    public ClientTSap() {
        socketFactory = SocketFactory.getDefault();
    }

    /**
     * Use this constructor to create a client TSAP that will start connections to remote TSAPs. You
     * could pass an SSLSocketFactory to enable SSL.
     *
     * @param socketFactory the socket factory to create the underlying socket
     */
    public ClientTSap(SocketFactory socketFactory) {
        this.socketFactory = socketFactory;
    }

    /**
     * Calculates and returns the maximum TPDUSize. This is equal to 2^(maxTPDUSizeParam)
     *
     * @param maxTPDUSizeParam the size parameter
     * @return the maximum TPDU size
     */
    public static int getMaxTPDUSize(int maxTPDUSizeParam) {
        if (maxTPDUSizeParam < 7 || maxTPDUSizeParam > 16) {
            throw new IllegalArgumentException("maxTPDUSizeParam is out of bound");
        }
        if (maxTPDUSizeParam == 16) {
            return 65531;
        } else {
            return (int) Math.pow(2, maxTPDUSizeParam);
        }
    }

    /**
     * Set the TConnection timeout for waiting for the first byte of a new message. Default is 0
     * (unlimited)
     *
     * @param messageTimeout in milliseconds
     */
    public void setMessageTimeout(int messageTimeout) {
        this.messageTimeout = messageTimeout;
    }

    /**
     * Set the TConnection timeout for receiving data once the beginning of a message has been
     * received. Default is 60000 (60seconds)
     *
     * @param messageFragmentTimeout in milliseconds
     */
    public void setMessageFragmentTimeout(int messageFragmentTimeout) {
        this.messageFragmentTimeout = messageFragmentTimeout;
    }

    /**
     * Get the maximum TPDU size parameter to be used by this TSAP
     *
     * @return the maximum TPDU size parameter
     */
    public int getMaxTPDUSizeParam() {
        return maxTPDUSizeParam;
    }

    /**
     * Set the maxTPDUSize. The default maxTPduSize is 65531 (see RFC 1006).
     *
     * @param maxTPDUSizeParam The maximum length is equal to 2^(maxTPDUSizeParam) octets. Note that
     *                         the actual TSDU size that can be transfered is equal to TPduSize-3. Default is 65531 octets
     *                         (see RFC 1006), 7 &lt;= maxTPDUSizeParam &lt;= 16, needs to be set before listening or
     *                         connecting
     */
    public void setMaxTPDUSizeParam(int maxTPDUSizeParam) {
        if (maxTPDUSizeParam < 7 || maxTPDUSizeParam > 16) {
            throw new IllegalArgumentException("maxTPDUSizeParam is out of bound");
        }
        this.maxTPDUSizeParam = maxTPDUSizeParam;
    }

    /**
     * Connect to a remote TSAP that is listening at the destination address.
     *
     * @param address remote IP
     * @param port    remote port
     * @return the Connection Object
     * @throws IOException is thrown if connection was unsuccessful.
     */
    public TConnection connectTo(InetAddress address, int port) throws IOException {
        return connectTo(address, port, null, -1);
    }

    /**
     * Connect to a remote TSAP that is listening at the destination address.
     *
     * @param address   remote IP
     * @param port      remote port
     * @param localAddr local IP
     * @param localPort local port
     * @return the Connection Object
     * @throws IOException is thrown if connection was unsuccessful.
     */
    public TConnection connectTo(InetAddress address, int port, InetAddress localAddr, int localPort) throws IOException {
        Socket socket;
        if (localAddr == null) {
            socket = socketFactory.createSocket();
            socket.connect(new InetSocketAddress(address, port), messageTimeout);
        } else {
            socket = socketFactory.createSocket(address, port, localAddr, localPort);
        }
        TConnection tConnection = new TConnection(socket, maxTPDUSizeParam, messageTimeout, messageFragmentTimeout, null);
        tConnection.tSelRemote = tSelRemote;
        tConnection.tSelLocal = tSelLocal;
        tConnection.startConnection();
        return tConnection;
    }

    public void setSocketFactory(SocketFactory socketFactory) {
        this.socketFactory = socketFactory;
    }
}
